Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
EGR System: Description
The Exhaust Gas Recirculation (EGR) system lowers combustion temperatures in combustion chamber, thereby reducing emission of oxides of nitrogen. Exhaust gas is drawn from cylinder head exhaust port into intake manifold riser portion through passages in cylinder head, intake manifold, and EGR valve.
The EGR valve vacuum diaphragm is connected to carburetor flange signal port through a Thermal Vacuum Valve (TVV). This controls EGR cold override. Opening carburetor throttle valve applies a vacuum to diaphragm, opening EGR valve to meter exhaust gas into intake manifold.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.